Identification of Infrasound Generation Mechanisms in a Bus

Abstract

This paper presents the results of experiments conducted to investigate infrasound generation in a bus. The bus was driven on a smooth road, both upwind and downwind, and with and without damping of window vibrations. It was also run on an uneven road for comparison. The results show that by damping the window vibrations it was possible to reduce the infrasound levels significantly. It is also concluded that higher air turbulence around the bus slightly increases the infrasound outside the frequency range of the axle resonance. Finally, it is concluded that road roughness as well as tyre “roughness” (unbalance or run-out) excite vibration and infrasound.